Fix `json_array_contains_value` function to use the `@>` operator for
checking if a JSON array contains a value in PostgreSQL. This is
necessary because the `has_key` function only works for string values.
Also, remove `get_rom_collections` method, as it was doing the same
thing as `get_collections_by_rom_id`.
Fixes#1441.
This change introduces PostgreSQL compatibility, by implementing the
following changes:
* Use `JSONB` instead of `JSON` for PostgreSQL databases. This is
achieved by creating a custom `CustomJSON` type that uses `JSONB` on
PostgreSQL and `JSON` on other databases, leveraging the variant
mechanism of SQLAlchemy.
* Add `is_postgresql` function to check if the current database is
PostgreSQL. Commonly used for migrations, but can be used to determine
how to build queries based on the database engine.
* Add `json_array_contains_value` function to check if a JSON array
includes a specific value. This function is needed as it's
engine-specific.
Support for PostgreSQL is on a best-effort basis, and it relies on the
community for continued support and testing. The project's main database
is MariaDB.
Closes#667.
The scanning process could try to fetch thousands of roms from the
database, one by one, which is very inefficient, especially when only a
few new roms are added to the library, as the overhead of database calls
is very high compared to metadata API calls.
This change introduces a new method in the roms handler to retrieve roms
by their file names in bulk, which is used during the scan process to
fetch a batch of roms at once, instead of one by one.
It also avoids the `@with_details` decorator when fetching roms during
the scanning process, as those details are not needed, and they were
adding unnecessary joins and data decoding.
As recommended by SQLAlchemy [1], this change makes a single
instantiation of the database engine and session maker, instead of one
entity per handler.
It also uses the provided `URL` constructor to better define the
database URL structure.
[1] https://docs.sqlalchemy.org/en/20/core/connections.html#basic-usage
